Phytochemical Screening and in Vitro Assessment of Antimicrobial and Antioxidant Potential of Andrographis Serpyllifolia-An Endemic Medicinal Plant from South India

The current study was aimed to investigate the phytochemical composition, antibacterial and antioxidant activity of A. serpyllifolia plant extracts. Phytochemical screening revealed the presence of alkaloid, tannins, steroids, terpenoids, phlobatannin, anthraquinones flavonoids, saponins and phenolic compounds. Quantitative analysis revealed the presence of saponins (4.2%) in high concentration followed by tannins (4.12%), phenolics (1.4%), alkaloids (1.2%) and flavonoids (0.98%). This study will provide phytochemical information for preparation of concentrated and effective extract of A. serpyllifolia. Petroleum ether, chloroform, benzene and methanol extracts of shade dried plant parts of A. serpyllifolia were tested for antibacterial activity against six strains of bacterial species, viz., Bacillus subtilis, Escherichia coli, Proteus, Pseudomonas aeruginosa, Klebsiella sps and Staphylococcus aureus using the standard agar disk diffusion method. All the extracts have shown significant activity against tested microbes with the inhibition zone ranged of 5.7-16.8mm. Among various solvent extracts studied petroleum ether extract showed a highest antibacterial activity followed by methanol, benzene, chloroform. Antioxidant potential of methanol extracts was determined by DPPH and ABTS free radical scavenging assay. The extracts showed a very good antioxidant property and the IC50 value was found to 268.12ìg/ml for DPPH assay and 398.46ìg/ml for ABTS assay. Ascorbic acid taken as control showed highest antioxidant power in the present study. The results suggest that A. serpyllifolia has promising antioxidant activity and could serve as potential source of natural antioxidant

Endophytic fungi and bioactive metabolites production: an update

Endophytic fungi are unique microbes that reside in the plant tissues and cause no harm or any symptoms of diseases. Although plants are the major source of modern drugs, there is a continuous search for new sources to obtain new lead molecules, with higher biological properties, for treating various diseases. Many plants are associated with several kinds of endophytic fungi capable of producing bioactive secondary metabolites. Thus, endophytic fungi can act as a reservoir of bioactive principles which are yet to be explored in detail. In addition, plant-endophytic fungal association stimulates plant growth, increase resistance towards phyto-pathogens, suppress the weed, and increase tolerance to abiotic and biotic stresses. In this chapter, various aspects of endophytic fungi including their symbiosis with plants, biological implications and important secondary metabolites production are discussed in detail. This information would certainly help to improve the pace of modern drug discovery

Characterization and bioactivity of oosporein produced by endophytic fungus Cochliobolus kusanoi isolated from Nerium oleander L

Bioactive compds. comprising secondary metabolites produced by endophytic fungi have wide applications in pharmacol. and agriculture. Isolation, characterization and evaluation of biol. activities of secondary metabolites were carried out from Cochliobolus kusanoi, an endophytic fungus of Nerium oleander L. The fungus was identified based on 18S rDNA sequence anal. There are no reports available on the compds. of C. kusanoi; hence, antimicrobial metabolites produced by this fungus were extd. and purified by fractionation using hexane, di-​Et ether, dichloromethane, Et acetate and methanol. Out of all the solvent fractions, the methanol fraction exhibited better antimicrobial activity which was further purified and characterized as oosporein. Oosporein from C. kusanoi exhibited broad spectrum in vitro antimicrobial, antioxidant and cytotoxic activities

Lactic Acid Bacteria Mediated Induction of Defense Enzymes To Enhance the Resistance in Tomato against Ralstonia Solanacearum Causing Bacterial Wilt

The biocontrol agent Lactic acid bacterium (LAB) was used against the bacterial wilt caused by Ralstonia solanacearum. The present investigation focuses on the role of defense related enzymes in imparting resistance to tomato plants against R. solanacearum. The LAB isolate was tested for its ability to induce the production of defense-related enzymes in treated tomato seedlings. Tomato seedlings were raised from LAB pretreated seeds, were challenge inoculated with R. solanacearum, harvested at different time intervals (0–72 h) and assayed for defense enzyme activity. The LAB treated seeds showed increase in germination percentage (6%) and seedling vigour index (259) compared with control. Treatment of tomato seedlings with LAB isolate induced a significant amount of Peroxidase (POX), Polyphenol oxidase (PPO), Phenylalanine ammonialyase (PAL), total phenolics and β-1,3-glucanase activities. The activities of PAL, POX, PPO and β-1,3-glucanase reached maximum at 24 h, 24 h, 32 h and 24 h respectively after challenge inoculation. Increased accumulation of phenolics was noticed in plants pre-treated with LAB. Native PAGE analyses of POX and PPO were carried out for the time course of enzyme activities and the isoforms of POX and PPO were examined. In field study, ten isolates of R. solanacearum treated plots yielded an average of 32.4–50 kg/m2 and LAB treated plots an average of 153.5 kg/m2. As compared to the control, LAB increased the yield by 15.3% (8.2 kg/m2) and the pathogen infected plants and pre-treated with LAB gave an average of 55% (28.3 kg/m2 compared to the infected plots). Field experiment results indicated that LAB exhibited 61.1% of disease reduction of bacterial wilt in tomato

Evaluation of in vitro antioxidant and antidiabetic activities from Amomum nilgiricum leaf extract

In the present study, hexane, ethyl acetate and methanol fraction of Amomum nilgiricum leaf was evaluated for antidiabetic efficacy, scavenging activities, followed by estimation of total phenol, total flavonoids. In the present study, a significant amounts of total phenolics (79.92±1.58 mg/g) and flavonoids (21.74± 0.89 mg/g) were showed from Ethyl acetae fraction. H2O2 scavenging activity (97.62±2.89%) with IC50 value of 78.57 µg/ml concentrations. Ethyl acetate fraction exhibited maximum inhibitory activity of glucose movement into outer solution across dialysis membrane at 250 µg/ml as compared to the control. The ethyl acetate fraction revealed maximum insulin secretory activity (130.5±3.66%) in RIN-m5F cells. Methanol fraction recorded maximum glucose uptake percent in yeast cells (67.08±1.68%) when compared to standard metronidazole (68.06±0.73%). This study scientifically validates the antidiabetic activity of A. nilgiricum. Hence, in view of its comparative hypoglycemic strength, it can work as a valuable healing agent in treating diabetes

Antimicrobial and Antioxidant Potential of Endophytic Fungi Isolated from Ethnomedicinal Plants of Western Ghats, Karnataka

A total of 79 endophytic fungal isolates were obtained from four wild medicinal plants-Tinospora cordifolia (Willd.) Hook.f and Thomson (Menispermaceae), Piper nigrum L., Piper longum L. (Piperaceae) and Zingiber officinale Roscoe (Zingiberaceae)from Western Ghats of Karnataka and screen them for antimicrobial and antioxidant potential.Among them, 16isolates depicting good antimicrobial activityby agar plug method (2.33mm-20.66mm) and agar well diffusion method (2.66mm-21mm)against human pathogens were identified by molecular techniques andsubjected to secondary metabolite extraction. The extracts were tested for their antioxidant potential by DPPH assay, ABTS assay, reducing power assay and total phenolic content. The isolate ABR4 (Fusarium solani) of Tinospora cordifoliashowed remarkable antimicrobial activity against the human pathogens at tested concentrations of 20-100µg/ml. The isolate GKS (Aspergillus terreus) of Zingiber officinale demonstrated excellent antioxidant activity (IC50-3.34) as compared to standard Gallic acid (IC50 – 5.54) which has not been reported previously. The findings of the study indicate that endophytic isolates serve as a potential source of novel bioactive products

Detection and Characterization of Antibacterial Siderophores Secreted by Endophytic Fungi from Cymbidium aloifolium

Endophytic fungi from orchid plants are reported to secrete secondary metabolites which include bioactive antimicrobial siderophores. In this study endophytic fungi capable of secreting siderophores were isolated from Cymbidium aloifolium, a medicinal orchid plant. The isolated extracellular siderophores from orchidaceous fungi act as chelating agents forming soluble complexes with Fe3+. The 60% endophytic fungi of Cymbidium aloifolium produced hydroxamate siderophore on CAS agar. The highest siderophore percentage was 57% in Penicillium chrysogenum (CAL1), 49% in Aspergillus sydowii (CAR12), 46% in Aspergillus terreus (CAR14) by CAS liquid assay. The optimum culture parameters for siderophore production were 30 degrees C, pH 6.5, maltose and ammonium nitrate and the highest resulting siderophore content was 73% in P. chrysogenum. The total protein content of solvent-purified siderophore increased four-fold compared with crude filtrate. The percent Fe3+ scavenged was detected by atomic absorption spectra analysis and the highest scavenging value was 83% by P. chrysogenum. Thin layer chromatography of purified P. chrysogenum siderophore showed a wine-colored spot with R-f value of 0.54. HPLC peaks with R(t)s of 10.5 and 12.5 min were obtained for iron-free and iron-bound P. chrysogenum siderophore, respectively. The iron-free P. chrysogenum siderophore revealed an exact mass-to-charge ratio (m/z) of 400.46 and iron-bound P. chrysogenum siderophore revealed a m/z of 453.35. The solvent-extracted siderophores inhibited the virulent plant pathogens Ralstonia solanacearum, that causes bacterial wilt in groundnut and Xanthomonas oryzae pv. oryzae which causes bacterial blight disease in rice. Thus, bioactive siderophore-producing endophytic P. chrysogenum can be exploited in the form of formulations for development of resistance against other phytopathogens in crop plants

GC–MS analysis of phytoconstituents from Amomum nilgiricum and molecular docking interactions of bioactive serverogenin acetate with target proteins

Amomum nilgiricum is one of the plant species reported from Western Ghats of India, belonging to the family Zingiberaceae, with ethno-botanical values, and is well-known for their ethno medicinal applications. In the present investigation, ethyl acetate and methanol extracts of A. nilgiricum were analyzed by Fourier transform infrared spectrometer (FTIR) and gas chromatography-mass spectrometry (GC–MS) to identify the important functional groups and phytochemical constituents. The FTIR spectra revealed the occurrence of functional characteristic peaks of aromatic amines, carboxylic acids, ketones, phenols and alkyl halides group from leaf and rhizome extracts. The GC–MS analysis of ethyl acetate and methanol extracts from leaves, and methanol extract from rhizomes of A. nilgiricum detected the presence of 25 phytochemical compounds. Further, the leaf and rhizome extracts of A. nilgiricum showed remarkable antibacterial and antifungal activities at 100 mg/mL. The results of DPPH and ferric reducing antioxidant power assay recorded maximum antioxidant activity in A. nilgiricum methanolic leaf extract. While, ethyl acetate leaf extract exhibited maximum α-amylase inhibition activity, followed by methanolic leaf extract exhibiting aldose reductase inhibition. Subsequently, these 25 identified compounds were analyzed for their bioactivity through in silico molecular docking studies. Results revealed that among the phytochemical compounds identified, serverogenin acetate might have maximum antibacterial, antifungal, antiviral, antioxidant and antidiabetic properties followed by 2,4-dimethyl-1,3-dioxane and (1,3-13C2)propanedioic acid. To our best knowledge, this is the first description on the phytochemical constituents of the leaves and rhizomes of A. nilgiricum, which show pharmacological significance, as there has been no literature available yet on GC–MS and phytochemical studies of this plant species. The in silico molecular docking of serverogenin acetate was also performed to confirm its broad spectrum activities based on the binding interactions with the antibacterial, antifungal, antiviral, antioxidant and antidiabetic target proteins. The results of the present study will create a way for the invention of herbal medicines for several ailments by using A. nilgiricum plants, which may lead to the development of novel drugs